whats the disadvantage to welding spidergears

You're making a locked rear end. No 'differential'. Same as a spool except NO WHERE NEAR as strong and is very likely to break (catastrophically).

Not advised. But some have gotten away with it.

Its the way we do it on our dirt track cars. The keyword is dirt!

I agree with both of these posts.

I actually welded up a set once for a drag car, and then didn't have the courage to run them. I was way too scared of something going bad, and the wheels coming to a screaching halt at 100 mph.

Dirt only

they need to be welded slow and with a nickle rod for cast iron

have not seen one hold up yet

but it was fun to break it,uslay going on and off the trailer,mud trucks and a few hooptees that was headed to the crusher

no way should you drive on the road with it IMO

if you need a locker,a mini spool is easy to do,a little cheaper and would hold up

if it junk you could try